The correct answer is B. The polar nuclei of the center cell
Step-by-step explanation:
Double fertilization is a particular and complex process of fertilization that occurs in plants with flowers. This process includes two sperm cells or masculine gametophyte and only one eff or female gametophyte. Because of this, in dobule fertilization one of the two sperm cells fuses with the egg or female gametophyte and this led to the development of seeds. The second masculine gametophyte, on the other hand, fuses with the polar nuclei of the center cell that is in the center of the plant embryo sac and these leads to the development of fruit. Also, after this, it is not possible any other sperm fertilizes the plant. Considering this, it can be concluded the second sperm cell fuses with the polar nuclei fo the center cell.